Monday, 4 May 2009

Proven statistically: Pigs can infect humans

REad the article below especially:" University of Wisconsin researchers, partly funded by the EmergingInfectious Disease department of the CDC, reported in 2002 that pigshad a definite role in generating genetically novel viruses, and evenurged that monitoring swine farmers "might be prudent.""

Monday May 4, 2009 (foodconsumer.org) -- While public health officialsare urging calm, emphasizing that the threat of the H1N1 virus may beeasing, "we are not out of the woods yet," said Dr. Richard of theCenters for Disease Control on a Fox News broadcast Sunday.

The CDC web site early Sunday listed 226 confirmed cases of the swineflu, which has spread into 30 states. But Bloomberg later reportedthat 241 swine flu cases had been reported in 34 states.

Dr. Anne Schuchat of the CDC was cited by Bloomberg as saying theincrease may be due in part to a backlog of specimen and testingresults.

On the international front, the World Health Organization stated onits website Sunday that 18 countries have officially reported 898cases of H1N1 infection. In Mexico alone there are 506 confirmed humancases of infection, including 19 deaths. The increase is purportedlydue to the fact that results from previously collected specimens arejust now in.

Pigs are not believed to be the vehicles spreading the H1N1 virus inthe outbreak; however, Canada reported on May 2 that the virus hasbeen detected in a swine herd in Alberta. Nevertheless, WHO said thepigs likely got the virus from a Canadian farm worker who had recentlyreturned from Mexico with flu-like symptoms.

And while the path and severity of the virus both remain unclear,scientists have been cautioning about the "pandemic potential" of theswine flu virus since August of2002 . Although cooked pork is believedto be safe to eat, a CDC funded study suggested that pigs can be theoriginators of a swine flu outbreak.

University of Wisconsin researchers, partly funded by the EmergingInfectious Disease department of the CDC, reported in 2002 that pigshad a definite role in generating genetically novel viruses, and evenurged that monitoring swine farmers "might be prudent."

"Because pigs can play a role in generating genetically novelinfluenza viruses," wrote the researchers, "swine farmers mayrepresent an important sentinel population to evaluate the emergenceof new pandemic influenza viruses."

In the report, Dr. Christopher Olsen, leader of the study, referred toprevious investigations into the swine flu virus done in the1960s:"Previous studies by Kluska et.al in the 1960 s suggested increasedrates of infection among persons in contact with pigs or working withswine influenza viruses," he wrote, confirming the virus can come fromthe farm animals.

Olsen wrote that infections of humans with swine flu viruses wereactually first verified by isolating swine influenza viruses from bothpigs and their caretaker on a farm in southern Wisconsin in November1976.

In the 2002 study, Olsen and his team evaluated "seropositivity," ora positive serum reaction to swine and human influenza viruses. Thestudy included 74 swine farm owners and their employees in rural south-central Wisconsin. Participants included 44 men, aged 13 to 59 years,and 35 women aged seven to 57 years. The control group included 114urban Milwaukee residents.

"The difference in the seropositive samples between the farmparticipants and urban control cohorts was statistically significant,"says the study.

The positive reactions to the virus were "significantly associatedwith being a farm owner, or a farm family member, living on a farm, orentering the swine barn more than four days a week," said Olsen andhis colleagues wrote. "In addition, pigs are clearly recognized ashosts in which genetic reassortment between human and avian virusescan produce novel strains of pandemic potential."

The researchers concluded that "given the frequency with which swinefarm workers in our study were exposed to influenza viruses from pigs,close monitoring may be prudent."

But it's really unknown where the virus that caused the currentoutbreak came from.